Mercury-vapor apparatus.



P. H. THOMAS.

MERCURY VAPOR APPARATUS.

APPLICATION FILED FBB.3, 1913.

Patented Sept. 15, 1914'.,

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WIT/VESSES P. H. THOMAS. MERCURY VAPOR APPARATUS.

APPLICATION FILED FEB.3, 1913. 1, 1 1 0,603.

] vl/Enron @www nronffr Patented Sept. 15, 1914.

' P. H. THOMAS.

MERCURY VAPOR APPARATUS.

APPLICATION FILED FEB.3, 1913.

Patented Sept. 15, 1914.4

3 SHEETS-SHEET 3.

55 ummm nunon H C l I 0 I l I l H I I I l l l 0 WITNESSES UNITED PATENT OFFICE.

PERCY H. THOMAS, OF UPPER MONTCLAIR, NEW

JERSEY, ASSIGNOR T0 COOPER HEWITT ELECTRIC CO., 0F HOBOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

MERCURY-VAPOR APPARATUS.

To all whom it may oom-ern Be it known that I, PERCY H. THOMAS, a citizen of the United States, and resident of Upper Montclair, county of Essex, State of N ew Jersey, have invented certain new and use ful Improvements in Mercury-Vapor Apparatus, of which the following is a specification.

My invention relates to mercury vapor rectiiiers and more particularly to certain methods oiE construction and specific features ali'ecting the operation of such devices as will be seen in the embodiments shown herein.

My apparatus is especially suited for practical use to give continuous and reliable service even with very heavy output or for translating devices requiring high voltages. I have embodied my general features of design as well as a number of novel details in av single device as a matter of convenience, but I wish it understood that the several features may be utilized separately where desirable.

The present rectifier is shown in Figures 1, 2, 3 and 4, where Fig. 1 is a half vertical section, F ig. 2 a halt horizontal section on the line A*B, Fig. 3 shows an enlarged anode and Fig. el shows a tight bushing for permitting the entrance and exit of a cooling pipe. Fig. 5 shows suitable circuits for operating the present rectifier from a three phase system.

In the first figure, 1 represents my recti Her, 2 is the main shell of the container which may be of steel, iron, nickel, copper or brass, or some other material which is a conductor of electricity and can be suitably formed.

3 is the cap or dome of the container, preferably made in one piece and may be of porcelain or earthenware or glass or other suitable material; this cap may, however, be made of conducting material if the various electrodes, cooling pipes and similar parts are insulated therefrom. This part is made dome shaped to help support the pressure of the atmosphere. To make this container perfectly gas tight it is, of course, necessary that the main cup, 2, be of impervious material and in one piece or that the joints be compressed or welded or otherwise closed Specification of Letters Patent.

Application filed February 3, 1913.

Patented Sept. 15. 1914. seriaiNo. 745,787.

tight. Similarly with the cap 3. To cover the ljoint between the cap and the cup I may weld or otherwise tightly secure a thin ilexible sheet of metal, 4, for example steel, to the llange. 5, ot' the cup 2. This sheet of metal, 4, may be formed to have an annular recess adapted to inclose the flange, (5, of the cap 3. '.l he horizontal portions ot this thin metal annulus may then be clamped to the llauge, (l, and mercury introduced at 7, thus giving a mercury sealed joint and pre- \.'enting the mercury from being spilled and also protecting the mercury.

The method of sealing the leading in conductors oi the anodes,l 8, will be described in connection with Fig. 3 and the entrance bushings, 9, for perniitting the entrance of the cooling pipe, 1U, will be described in connection with Fig. 4c. The connection for receiving the rectified current may be welded or otherwise secured to the outside of the cup, 2, as shown at 11 so that no opening in the container is required for connection to the cathode.

The anodes, S, are placed symmetrically around the outer portion of the exhausted space, each being supported by and having its lead pass through the container cap 3. rThe anodes are hollow and contain a vaporizable material such as water or mercury and the interior space is connected with a coil'ot' pipe, 12, outside of and above the cap and a return connection is provided at 1i. The cooling tubes, 12, are carried in a block, 52, which may be screwed on the top of the sleeve 29. Y

A flange, 14, shown also in Fig. 2 supported by the cap, 3, surrounds each anode leaving an opening at the bottom and an opening toward one of the other anodes. The cooling coil, 12, is supported on the rest, 15, suitably formed in the cap 3. This rest, 15, forms a pocket containing` the lead of the anode, 8, and serves to contain mercury, 16, for a. seal for this lead.

As a means of disposing of a portion of the heat liberated in the container, I utilize the cooling coilor the pipe, 10. This coil of-pipe is carried upon a ring, 17, which may be of porcelain, earthenware, fused quartz, soapstone or other suitable insulating material. This ring, -17 serves both as an insulating support for the coil 10 and to confine the point at which current enters the cathode to the central portion of the container'. I provide arecess, 18, in the ring 17 to prevent the formation of a continuous stream or surface of mercury from the scum collecting thereon between the coil, 10, and the mercury, ISL/which constitutes the vaporizable cathode. I also provide a passageway, 20, for maintaining a uniform level in the mercury inside and outside of the ring, 17. The top of the coil, 10, is guided and steadied by the cap, 3, which is suitably shaped for this purpose. The arrangement of the pipes, 10, is such that the openings between the pipes in one row are covered by the pipes themselves in another row, the object being to require all the mercury vapor or current of electricity passing through the coil to follow a devious and indirect path. The plate, 21, which may be an annulus or which may be of sep arate pieces is placed upon the top of the inerciu'youtside of the ring, 17, to protect the anodes, S, both from mercury and from electric cifects.

Fig. shows in plan most of the several parts already described and needs no further explanation.

The terminals of the coil, 10, are carried through the wall of the cup, 2, through the bushings, 9, 9, and insulating joints, 23, 23, are introduced outside cf the container to l-:eep the coil, 10, out of contact with external conductors. 'These insulating joints include external insulating sleeves, 24, and internal insulating sleeves, Q5. At 2G I have shown a connection for exhausting the gases from the rectifier which may be welded or otherwise tightly secured to the wall of the cup 2.

In Fig. 3, S is a main anode, 27 is a portion of the cap of the container, 13 the return tube from the cooling coil 12, and 28 is the lead and vapor tube connecting the pipe, 12, with the inside of the anode, 8.

The tube, 28, is brazed or welded to the sleeve, 29, which, as well as the tube QS, may be of steel, so as to be air tight.

30 and 31 are nuts threaded on to the sleeve, Q9, for the salie of clamping the rim, 27.

32 is a Washer under the nut 31., and 33 is a diaphragm serving to inclose the mercury, 16, shown in Fig. 1.

31 is a cap of graphite, of steel or other material, fitting closely against the top of the anode, 8, Vand against the under surface of the rim, 27, to protect the upper portion of the anode, 8, and its lead. I have shown the level of theV mercury or other vaporizable material just within the anode, 8, at the point, 35. I have shown in Fig. 1 the joint between the sleeve, 29, and the rim, 27, is sealed by mercury, 16. A passageway, 36, is provided to permit the entrance of the sealsleeve, 38, from the rim, 3S).

44, 45, 4G and 47 are various washers located as shown. The joints are sealed by mercury in the two annular spaces 48 and 479 which are filled by the passageways 50.

when the mercury1 is in place a cap bolt, 51,

may be placed in the outlet, of the passageways, 50, to confine the mercury.

The operation of this rectifier is as follows. The flow of current between the anodes and the cathode occurs by way of the central space in the container through the coil of the pipe, 10, to the side openings in the flanges, 14, to the anodes, 8. The negative flame, so-called, discharges directly upward into the dome of tlie cap, 3, and the anodes are separated therefrom by the coil of pipe, 10, the openings in any one row of pipes being covered by Ithe pipes ofat least one other row. This is a very effective arrangement since the anodes arel protected from all sorts of possible deteriorating influences, whether these be the effect of the negative flame (sometimes called emanations from the cathode), the spattering of mercury, the dropping of mercury or the effect of electric charges, of a positive character whichmay be drawn toward an anode; from the latter, since I connect the' coil pipe, 10, to a source of potential which is intermediate between the potential ofthe cathode and that of the non-operating anodes. This I accomplish as shown in Fig. 5 or as provided in my application Serial Number 664,169, filed December 6th, 1911.

In case itis desired to utilize separate electrodes as means for protecting anodes of various polarities, the several rows of pipe shown in Fig. 1 may be made separate or be insulated from one another suitably for connecting to a supply of electrical energy in the manner shown in my last mentioned co-pending application. In Fig. 1 these coils are shown as insulated by a ring 17 in the manner shown in my last mentioned co-pending application.

My rectilier is unusually well adapted to theA disposal of the heat liberated by the flow of current and to meeting the other unfavorable effects thereof. Not only does the container, and especially the metal part thereof, expose a large surface for the disposal of heat, which surface may be immersed in a cooling ,liquid or otherwise artiiicially cooled, but I provide in the coils, V10, a very powerful means for cooling the vapor, through the circulating fluid which maybe passed through this pipe. By causin'g the entering water to traverse first the outer row of pipes, I apply the cooling means at its most effective temperature to the remnants of the vapor which has not been' condensed by the inner rows of pipes. The pipes, 10not onl thus have a very intimate contact with e vapor to be condensed but serve to a certain extent to limit, by throttling, the amount of vapor escaping into the outer sections of the vacuum space, where the anodes are located, so that the cooling provided by the walls of the cup, 2, will be able to maintain a very rfect vacuum around the anodes. This 1s well known to be one of the most e'ective means for preventin the diiculty known as short circuiting. hus,

in eiect, the coils of the pipe, 10, separate the central portion of the rectifier where the negative llame and high pressure mercu vvapor are found, from the outer region whlch may be maintained at avery much lower temperature. This separation is both mechanical and electrical, at least as far as the protection of anodes from deteriorating electric effects is concerned. The location of the exhaust outlet, 26, in the anode region is favorable, since at this oint the amount of mercury vapor is'relatively small, since 'it is the natural collecting place /for noncondensable gases, and since this is the re- -gion -in which purity is more particularly required. It is clear that should any mer-- cury have a tendency to drop or splash from the ipes, 10, this could not reach the anodes in view of the flanges, 14, and yet the passages for the flow of current from cathode to anode are wide and free as far as their sectional area goes, though, of course, they are very indirect.

In many places, I prefer to use mercury as the cooling material in the hollow anodes, 8, since it is desirable that this anode, during operation, be neither very cold nor extremely hot. Obviously, if atmospheric pressure is present in the tubes 12, therewill be initially little or no vapor-ization of the mercury within the anode 8 and, as little cooling is taking place at this time, the temperature of the anode will rise rapidly. When, however, the boiling point of mercury at atmospheric pressure, which is in the neighborhood of three or four hundred degreesA centigrade, is reached, large volumes of mercury vapor will be produced which will pass up the tube, 28, and be condensed in the 'coil ofthe pipe, 12, and then returned to the interior of the anode through the tube, 13. The effectiveness of the tubes, 12, may be greatly increased bythe use of' air blastcr -cooling liquid. By changing .the liquid in the anode, 8, or the pressure in the tube, 12, the point at which vsporization ofthe inside liquid occurs an the tem rature of the anode can be thus contrclle To maintain atmospheric pressure in the' tube, 12, I may insert a porous plug, as shown. Another advantage of t e/use o mercury within the anode 8 is that the condensa'tion in vthe tube, 12, tends to take place at a relatively very high temperature such as the three or four hundred degrees centigrade already spoken of, which will greatly assist the dispersal of heat from the tubes, 12. i

The plate, 2 1, serves to protect the anodes, 8, electrically and mechanically from the presence of the mercury 19.

In Fig. 5, 53, 54 and 55 are three delta connected transformer primaries; 56, 57 and 58 are respectively the corresponding secondaries for these primaries. These secondaries are connected to the six main anodes in the same order around the container in which the sequence of the phases flow. In other words, the two anodes adjacent to any given anode are the anodes nearest in potential thereto. By this means it is possible to keep at its minimum the potential between an adjacent pair of main anodes. The central points of the secondaries 56, 57 and 58 are connected' by the conductor, 59, to the negative side of a work circuit, 60, while the cathode, 19, of the device is connected through the choke coil, 65, to the opposite side of the work circuit. I provide a switch, 66, whereby, if desired, the coil, 65 may be short circuited.

This coil may act either vto smooth out the waves or to keep alive the rectifier as may be required'. In case -no other keeping alive means are provided, this coil, 65, will maintain continuity of current in the cathode, even 4 in the case when the counter electromotive force of the motor, 67, in the work circuit is greater than the minimum points of the effective supply voltage. The cooling coil, 10, isA connected lthrough the inductance, 64, and resistance, 63, to the contact arm, 62, which may be connected@ various oints on the potentiometer shown at 61. he eiect of this potentiometer connection is to permit any given condition of. potential in the negative direction betweenthe cathode, 19, and the cooling coil, 10.

'I may provide, though this is not necessary, a keeping alive primary whose secondary is-sho'wn at 68 connected through 'the inductances 69 and 70 to two suppleinductanee, 64, serve to limit the amount of leakage current taken up by.A the cooling coil, 10, operating as a protecting negative electrode, and'also preventing an acci ental disturbance .therein from `establishing continuous Loperation upon this coil as a cathode. Y I

If desired, I may dispense with this use of the coolin coil by .opening the switch, 74. It shou d be understood that this rectifier may be used with other types of circuits, for example with any of the appropriate circuits in my co-pending a plication Serial Number 745,786, filed ebruar 3rd, 1913.

t will be understood that it may be desirable to operate this rectifier in practical service with a ,continuously operating vacuum pump to preserve the highest degree of vacuum and reliability. It will be further understood that the substance of the principles and features shown in the present rectifier may be attained by the use of 4various mechanical and electrical equivalents therein, which it is not necessary liere to illustrate. I wish to include all suchy modifications in my invention. While I have described the mercury, 19, as the material of the cathode, I do not wish to limit my invention to this particular material for other materials will serve as well under appropriate conditions. Furthermore many of the combinations and structures of the present apparatusv may be utilized in` vapor apparatus not intended for rectification and these also are included in the 'scope of the present invention. Where relatively low volta es for small currents are to be utilized, 1t may not be necessary to use all of\ the features herein shown. For example, the flanges, 14, may be omitted or fewer coils of pipe utilized or theplates, 21, dispensed with, or the cathode material, 19, may be' included in an insulating cup not being in electrical connection with the conducting portion of the container.

Any suitable means may be utilized for starting this rectifier, either high potential,

, or one or more auxiliary electrodes, which may be introduced through the cap, 3, in the central portion, if desired, or may be located in the portion ofthe container inclosing the main anodes. It will frequently be desirable to supply means for exciting the cathode continuously or intermittently as by passing direct current continuously therethrough in the positive direction. All these conditions, as Well as various means for improving the vacuum by chemical absorption or by the seclusion` of residual gases in separate chambers may be combined in the present apparatus without departing from`this invention.

I claim as my invention:

1. A mercury vapor rectifier comprising an exhausted container, includi a hollow. lower -portion, and an insulatin dome shaped up er portion, an active cat ode in the centra portion of said container, a plurality of main anodes in the outer portion of said container and an interposed coil of cooling tubes between said cathode and said anodes.

2. A mercury vapor rectifier com rising an exhausted container, including a ollow lower portion, and an insulatm 'dome shaped uplper portion, an active cat ode in the centra portion of said container, a plurality of main anodes in the outer portion of said container and an interposed coil of cooling tubes between said cathode and said anodes, said cooling coil being of conducting material and being maintained at a potential negative with respect to that of the cathode.

3. A mercury vapor rectifier comprising an exhausted container, including hollow lower portion, and an insulating dome shaped upper portion, an active cathode in the central portion of said container, a .plurality of main anodes in the outer portion of said container and an inte sed coil of cooling tubes between said cat ode and said anodes, and means for maintaining said coil at a potential below that of the cathode, said means consisting of a resistance coil with 'rectifier and a connection from said shunt to said cooling coil.

4.1A mercury vapor rectifier comprising a container composed principally of conducting material, a. plurality of anodes therein, a cathode therein and' a cooling coil of conducting material electrically insulated therefrom. Y A 5.' A mercury vapor rectifier comprisin` an exhausted container having a series o' anodes therein in combination with an insulating flange 4with a wideopening therein surrounding each anode, the openings in the several chambers formed by the flange being faced in the same direction along a line connecting the anodes.

6. A mercury vapor rectifier comprising an exhausted container having a series of anodes therein in connection with a flange with a wide opening therein/ surrounding each anode, the openings in the several chambers formed bythe flange being faced in the same direction along a line connecting the anodes.

7. A mercury vapor rectifier comprising a container made up of a cup shaped hollow lower portion and a dome shaped insulating upper portion, mercury in the bottom of said cup shaped portion constituting a cathode, an insulating ring inclosing a central portion of said mercury electrode, a coil of conducting cooling pipe resting on said. insulating ringV an extending upward into taps shunted on the receiving circuit of sail liso anodes, and means for maintaining the po-l close proximity to said dome shaped top, a series of anodes arranged in a circle out-k side said cooling pipe, said anodes being carried by said top, partly closed circular fianges surrounding said anode, opening circumferentially, external cooling condensing means connected with the interior of said tential of said cooling coils below that of said cathode. A

8. In an elrha'ustedl vapor rectifier, means for sealing the joint between two parts therefor, one of said parts being of metal, said means consisting of a flexible thin sheet of metal welded near one edge to the said metal portion of the container `on the peessure surface exposed to the other part and means for clamping the other edges of said thin metal piece to the last named portionv ofthe container and mercury acting :is a seal disposed in the pocket thus formed.

Signed at New York in the county of New York and State of New York this 1st day of February, A. D. 1913.

PERCY H. THOMAS. Witnesses:

WM. H. CAEL, THos. H. BROWN. 

